You should move your air 1x per 5 min, not 5 times per 1 min! 500 cfm would be suited for a room of 2000+ cubic feet, assuming it is installed properly. I have test many fans, and the majority of the time the cfm is inaccuate(and this may be the your issue). A 100 cubic foot room (@ size of a large fridge) can be vented with a small squirrel fan or even computer fans. if the carbon filter is installed corrected in your exhaust it will remove the majority of smell, and you must also anticipate about 5% resistance to your exhaust system. @trichlone fiend I can assure you haven't installed a 500cfm in a 100^3ft room, as it would be too powerful and literally suck your plants out of the pots! In a larger room, if your lighting exhaust connects to your room exhaust, a 500cfm would be feasible for a 1000 cubic foot room. Ventilation is very important, always make sure you have at least 1 room exhaust fan, if professional lighting, a fan for that, and fans for circulating air. If you do not use CO2 make sure you have an opening or another fan to bring fresh air inside. Exhaust is for temp control and CO2. Please review information, as this will confuse beginner gardeners and hurt/destroy their garden....it depends if you get the appropriate size carbon filter, and appropriate size fan. They both come in sizes of CFM's (cubic feet per minute)...this is an estimated measurement of the air it moves in a minutes time. You need to move your air 5 times per minute through each to be safe. So, if you have a hunderd sq feet to exaust, you'll want 500 cfm for both filter and fan.